Try this option:
1) if csc(u)=9, then 1/sin(u)=9 and sin(u)=1/9;
2) if sin(u)=1/9, then cos(u):

3) 



-84
21x4=84 plus the negative
Hi!
4.2+0.6/3-5(0.9-0.5) = 4.2 + 0.2 - 5*0.4 = 4.4 - 2 = 2.4
Hope this helps!
I don't know the answer, but I suggest downloading the app: PhotoMath. It scans a math problem and shows you how to complete the problem. I hope this helped~!